JP4494023B2 - Gas generator for airbag - Google Patents

Description

  The present invention relates to a gas generator for an air bag that protects an occupant from an impact.

There are various requirements for an air bag gas generator incorporated in an air bag system mounted on an automobile from the viewpoint of occupant protection. One of the requirements is that it can operate reliably over the normal service life (10 years) of the vehicle to be mounted.
In order to reduce the size of the gas generator, it is desirable to use a gas generating agent having a low combustion temperature so that the coolant / filter can be made simpler. When such a gas generating agent having a low combustion temperature is used, gas components such as NOx can be further reduced during combustion of the gas generating agent, which is more desirable.

However, it is known that the gas generating agent having a low combustion temperature has a poor ignitability as a general tendency. On the other hand, from the viewpoint of ensuring the reliability of the operation of the gas generator, it is desired that the gas generating agent has good ignitability and combustibility.
Therefore, gas cleaning, weight reduction of the gas generator, and ensuring the reliability of operation are technical issues that conflict with each other in terms of ignitability and combustibility of the gas generating agent.

  Furthermore, the output of the gas generator will be changed depending on the vehicle model to be installed, but changing the use of the component container and the parts inside the container each time will not only increase costs, It also causes assembly.

As prior arts related to the present invention, there are Patent Document 1 and Patent Document 2. Among them, the gas generator disclosed in Patent Document 1 ignites and burns a transfer charge by the operation of an igniter, and ignites and burns the gas generating agent with the flame. At the same time, the document 1 does not mention the combustion temperature of the gas generant, and does not suggest any problems caused by the combustion temperature. Moreover, the gas generator shown by patent document 2 ignites a transfer agent by the energization ignition of an ignition tool, and burns a gas generating agent with the flame. In particular, in this document 2, since the gas generating agent of a nitrogen-containing organic compound is inferior in ignitability, an ignition chamber for restricting the outflow of gas in the circumferential direction is provided. At the same time, the structure described in this document 2 cannot effectively burn a gas generating agent having a lower combustion temperature. In this document 2, two or more kinds of gas generating agents having different combustion temperatures are used. Since no mention is made of the use of gas, it is impossible to adjust the output by combining gas generating agents having different combustion temperatures.
JP 11-334517 A International Publication WO01 / 72560

  The present invention improves the flammability of the gas generating agent during operation, can ensure the reliability of the operation, and at the same time can reduce the weight and generate clean gas, and further ensure the operation of the gas generator. It is an object of the present invention to provide a gas generator for an air bag that can easily adjust the output while achieving sufficient performance.

  In the gas generator according to the present invention, a gas generating agent having a high combustion temperature and a gas generating agent having a lower combustion temperature are used in combination, and a gas generating agent having a low combustion temperature is generated by the gas generating agent having a high combustion temperature. The above problem is solved by igniting and burning the agent.

  That is, the present invention is a gas generator comprising a housing having a gas discharge hole, an ignition means as an operation start means of the gas generator, and a gas generating agent that generates a gas for inflation by ignition and combustion, The gas generating agent is filled in one or more combustion chambers defined in the housing, and at least one of the combustion chambers is filled with at least two kinds of gas generating agents that generate different combustion temperatures. A gas generator for an airbag is provided.

  In the gas generating agent, two or more kinds of gas generating agents having different combustion temperatures are filled in the same combustion chamber. The combustion temperature of the gas generant can be determined by theoretical calculation, for example, by NEW PEP (NEW PROPELLANT EVALUATION PROGRAM) created based on the basic program of NAVAL WEAPONS CENTER in the United States. In such a gas generator, since the ignitability of the gas generating agent generally correlates with the combustion temperature, the gas generating agent having a high combustion temperature is first ignited when the gas generator is operated. It is desirable to ignite and burn a gas generating agent having a low combustion temperature by a flame. As a result, the combustion temperature generated in the combustion chamber is reduced by the amount of the gas generating agent having a low combustion temperature as compared with the case where the gas generating agent having a high combustion temperature is used. As a result, the coolant / filter used for gas purification and cooling should be simpler (for example, with a simple structure that does not require a high level of combustion gas purification effect or combustion gas cooling effect). In addition, gas components such as NOx can be reduced. The filling amount of the gas generating agent having a low combustion temperature is preferably larger than the filling amount of the gas generating agent having a high combustion temperature.

  In the operation of the gas generator, first, the gas generating agent having a high combustion temperature is ignited, so that the gas generating agent having a low combustion temperature can be reliably ignited and burned by the flame. Because the combustion lasts for a long time, especially by using a gas generating agent with a high combustion temperature (because a gas generating agent with a low combustion temperature is exposed to a high temperature atmosphere for a long time), the flame causes a combustion temperature. The combustion of the gas generating agent having a low value can be made more reliable. Therefore, the combination of such gas generating agents can sufficiently ensure the reliability of the operation of the gas generator, thereby achieving gas cleaning while achieving gas cleaning and weight reduction of the gas generator. Thus, it is possible to provide a gas generator in which the certainty of operation is ensured. In addition, when mixing a gas generant with a high combustion temperature and a gas generant with a low combustion temperature, the combustion temperature of the entire gas generant used in the gas generator can be adjusted by changing the mixing ratio. it can. Therefore, by adjusting the filling ratio of both gas generating agents, it is possible to finely control the output of the gas generator, there is no need to change the components of the gas generator according to the required output, Further, it is possible to eliminate the possibility of erroneous assembly of parts due to the change of the component parts.

  However, in order to obtain the above effect in the present invention, it is necessary that two or more kinds of gas generating agents filled in the same combustion chamber have different combustion temperatures. The gas generator of the present invention uses a combination of gas generating agents having different combustion temperatures to effectively burn a gas generating agent having a low combustion temperature and reduce the combustion temperature of the gas generating agent as a whole. In addition, it is intended to further clean the gas and reduce the weight of the gas generator.

  In the gas generator of the present invention, the shape and dimensions of the gas generating agent may be the same between the gas generating agent having a low combustion temperature and the gas generating agent having a high combustion temperature, which are disposed in the same combustion chamber, May be different.

  In addition, the gas generating agent generates heat at the same time as the gas for inflating the airbag by combustion, but the calorific value when the gas generating agent burns is absorbed not only by the generated gas but also by the solid residue, A high calorific value from the gas generating agent does not necessarily increase the combustion temperature of the gas generating agent. Therefore, it is difficult to adjust the output according to the ratio of the gas generating agents having different calorific values. On the other hand, in the gas generator of the present invention, at least two kinds of gas generating agents having different combustion temperatures are used, and these gas generating agents are arranged in the same combustion chamber, thereby ensuring the combustion temperature of the gas generating agent. Can be adjusted. Such a gas generator of the present invention may be of a single type with one ignition means, or may be of a dual type with two ignition means. Alternatively, the ignition means may be three or more (multi-type) gas generators.

  In the gas generator of the present invention, of at least two types of gas generating agents arranged in the same combustion chamber, the gas generating agent having a high combustion temperature can ignite and burn the gas generating agent having a low combustion temperature. Can be used in The amount of the gas generating agent having a high combustion temperature can be determined by the composition, composition ratio, shape, size, and amount of the gas generating agent having a low combustion temperature.

  Also, gas generators may have different output requirements during operation depending on the vehicle model to which they are installed. Changing the internal structure (or changing the components) for each output may cause a problem of incorrect assembly. Increases nature. In order to change the output, the filling amount of the gas generating agent and the coolant such as a filter or a coolant are generally changed.

  Therefore, in the present invention, it is desirable to fill the same combustion chamber so that the amount of each gas generating agent having different combustion temperatures can be arbitrarily adjusted in the combustion chamber. Such adjustment of the filling amount of each gas generating agent is performed by using the amount of each gas generating agent filled in the same combustion chamber, the amount of all gas generating agents charged in the same combustion chamber, and filling the same combustion chamber. Can be achieved by adjusting the ratio of the gas generating agent having a high combustion temperature and the gas generating agent having a low combustion temperature. For example, in addition to considering the ignitability of the gas generating agent having a low combustion temperature, It can be determined in consideration of the combustion temperature occurring in the chamber. When gas blending agents having different combustion temperatures are used in combination and the mixing ratio thereof is adjusted, the temperature of the gas generated from the combined gas generating agent can be varied, so that the output can be finely adjusted. That is, by changing the mixing ratio of the gas generating agents having different combustion temperatures, the gas temperature generated from the entire gas generating agent can be adjusted, and further the output of the gas generator can be adjusted. In particular, when changing the ratio of the gas generating agent with a high combustion temperature and the gas generating agent with a low combustion temperature filled in the same combustion chamber, the volume of the entire combustion chamber does not change, so an extra gap is created in the combustion chamber. This is preferable. The details of the gas generating agent that can be filled in the same combustion chamber will be described in Examples described later.

  In addition, gas generating agents with different combustion temperatures filled in the same combustion chamber are filled in the one combustion chamber in a uniformly mixed state, and at least any kind of gas generating agent is added to the one combustion chamber. They may be biased in the combustion chamber. In particular, when any of the gas generating agents is unevenly packed, the gas generating agent having the higher combustion temperature of the two or more kinds of gas generating agents is directly applied by the ignition means (electric igniter or the like). It is desirable to arrange it at a position where it is ignited. In many cases, the “position directly ignited by the ignition means (electric igniter etc.)” is the vicinity of the ignition means, and the flame of the ignition means is other members (tubes etc.) or other configurations. When guided to a place, it is the position where the flame of the ignition means is guided. In particular, “in the vicinity of the ignition means” means that the gas generating agent having a high combustion temperature is in contact with the ignition means, or is ignited by the ignition means earlier than the gas generating agent having a low combustion temperature even if it is not in contact. It means that it is within the distance range that can be performed.

  As described above, by arranging the gas generating agent having the higher combustion temperature at a position where it is directly ignited by the ignition means (electric igniter or the like), the gas generating agent is ignited and burned quickly and reliably, As a result, all gas generating agents can be ignited and burned quickly and reliably, thereby improving the operational reliability of the gas generator. That is, since the gas generating agent generally has good ignitability when the combustion temperature is high, the gas generating agent having the high combustion temperature can be directly ignited and burned only by the igniter. Therefore, when gas generating agents with different combustion temperatures are used, the gas with the higher combustion temperature can be obtained by placing the one with the higher combustion temperature closer to the igniter (contacting or leaving a distance that can be ignited). The generating agent can be easily and reliably ignited and combusted, and the ignition / combustibility of the gas generating agent having a low combustion temperature can be improved by the flame. Therefore, when each gas generating agent filled in the same combustion chamber is packed in a plurality of layers for each gas generating agent having different combustion temperatures, the igniter, the gas generating agent having a high combustion temperature, the combustion temperature Are preferably arranged in the order of low gas generating agents or ignited.

  In addition, the ignition means can be configured with only an electric igniter, and can also be configured with a transfer charge. In this case, the transfer charge is ignited by the operation of the igniter, and ignition energy is generated in the form of flame, high-temperature gas, etc., and this ignition energy ignites and burns the gas generating agent having a high combustion temperature, and the combustion The gas generating agent with a low combustion temperature is ignited and burned with energy. The charge transfer used as such ignition means amplifies the thermal energy generated by the operation of the igniter and plays a role in effectively burning the gas generating agent, and substantially contributes to the expansion of the airbag. It is different from the gas generating agent having a high combustion temperature in the present invention in that it is not used for the purpose of generating gas. Therefore, in the present invention, a gas generation efficiency of less than 1.2 mol / 100 g can be regarded as a charge transfer agent. In general, a mixture of boron and potassium nitrate (glass stone) is used as such a transfer agent. At the same time, in order to reduce the size and weight of the gas generating agent, it is desirable that the ignition means is composed only of an electric igniter, and the gas generating agent having a high combustion temperature is directly selected only by the electric igniter. It is preferable to ignite and burn.

  In addition, such conventional explosives are used in powder form, have a short combustion duration and burn out instantaneously, the amount of generated gas is very small, and not only inflating the airbag, and mainly It is clearly distinguished from the high-combustion gas generating agent used in the present invention in that it is a heat residue generated by combustion and fine adjustment of the output of the gas generator is impossible. .

Further, when each gas generating agent filled in the same combustion chamber is filled in a plurality of layers for each gas generating agent having different combustion temperatures, at least two kinds of gas generating agents arranged in the same combustion chamber Is preferably filled in a space partitioned by a partition member having a communication hole for each type in the one combustion chamber. By partitioning one combustion chamber with the partition member, each gas generating agent can be easily filled, and mixing of the gas generating agents by vibration in a state of being mounted on a vehicle can be prevented. That is, by using the partition member, the gas generating agent having a low combustion temperature can be surely present at an intended place (eg, in the vicinity of the ignition means).
In addition, when any or all of the combustion chambers are partitioned by a partition plate, the partition is partitioned by a partition plate having the communication hole, and further, by being deformed, moved, destroyed, exhausted, etc. by combustion of the gas generating agent. It is also possible to partition with appropriate cushion members formed to communicate the spaces. The cushion member is formed into a flat plate shape that matches the cross-sectional shape of the installed combustion chamber using, for example, a resin material or other appropriate material, and is formed into an appropriate three-dimensional shape that can be disposed in the combustion chamber. Can do. Of course, the cushion member may be formed with a communication hole for communicating the partitioned spaces. Further, in this partition member and cushion member, in addition to forming the communication hole, the partition member and the cushion member are formed in such a dimension as to form a gap with the member defining the combustion chamber, and the gap (for example, the wall surface of the combustion chamber) A gap formed between the edge of the partition member and the like can be used instead of the communication hole.

  The partition member is preferably installed as a partition for the combustion chamber according to the amount of each gas generating agent filled in the combustion chamber in which the partition member is disposed. That is, it is desirable to arbitrarily adjust the gas generating agent having a high combustion temperature and the gas generating agent having a low combustion temperature in accordance with the ignitability, usage amount, usage ratio, etc. of each gas generating agent. If the space volume for filling each gas generating agent can be adjusted appropriately, each gas generating agent can be filled accurately without causing mixing due to vibration when the vehicle is mounted or damage of the gas generating agent. be able to. Such a partition member can be fixed in the combustion chamber by, for example, press fitting so that the combustion chamber can be freely partitioned in accordance with the filling amount of each gas generating agent.

  A communication hole is formed in the partition member, and the spaces in which the communication holes are partitioned communicate with each other. The communication hole is formed so as not to affect the combustion performance of the gas generating agent, and the combustion performance of the gas generating agent disposed in the space upstream of the partition member (away from the gas discharge hole). In order to adjust the combustion internal pressure in the space, the opening area of the communication hole (if there are a plurality of communication holes, the total of all of them) and the surface area of the gas generating agent can be related. . Furthermore, this communication hole is closed with aluminum tape or the like with a thickness of about 50 μm to 100 μm (thickness that combines the adhesive layer and the base), and ruptured by the pressure during combustion, or covered with a silicon cushion, etc. It is also possible to burn out with heat.

  Even if one combustion chamber is partitioned by a partition member as described above, a communication hole is formed in the partition member, and each space in which different gas generating agents are accommodated can communicate with each other. Because the gas generating agent starts combustion due to the operation of one igniter, the space combined with the partition member is a single combustion chamber, and each of the partitioned spaces Does not become a combustion chamber. That is, in the present invention, the one or more “combustion chambers” defined in the housing are spaces defined according to ignition means for igniting and burning the gas generating agent filled therein. The one or more kinds of gas generating agents filled in any one of the combustion chambers are ignited and combusted in association with the operation of any one of the ignition means. Therefore, even if the partition member is arranged in the combustion chamber and the space in which each different gas generating agent is stored is partitioned by the partition member, they burn in relation to the operation of one igniter. If so, the gas generating agents are considered to be disposed in one and the same combustion chamber. This is not only a single type gas generator, but also a dual type gas generator in which two combinations of combustion chambers and corresponding ignition means are provided, or a multi-type gas generator in which three or more such combinations are provided. The same applies to the case of.

  In particular, when the gas generator is dual or multi-type, two or more kinds of gas generating agents having different combustion temperatures are arranged to coexist (mixed) in all the combustion chambers provided in the gas generator. It is also possible to arrange them only in any one combustion chamber (mixed).

  In the gas generator of the present invention, at least two kinds of gases that cause the different combustion temperatures to have sufficient ignitability while keeping the combustion temperature of the entire gas generating agent low while having the above-described configuration. Of the generating agents, the combustion temperature of the gas generating agent having the highest combustion temperature is preferably 1700 to 3000 ° C, and the combustion temperature of the gas generating agent having the lowest combustion temperature is preferably 1000 to 1700 ° C. Furthermore, the gas generating agent having the highest combustion temperature among the two or more types of gas generating agents charged in the same combustion chamber is preferably one that generates 1.2 mol / 100 g or more of gas.

  When a gas generating agent having a high combustion temperature and a gas generating agent having a low combustion temperature are partitioned by a partition member and disposed in one combustion chamber, it is desirable that the gas generating agent having a low combustion temperature is larger in the filling ratio. As a result, the temperature of the gas generated from the entire gas generating agent is lowered, the amount of coolant can be reduced, and the gas generator can be reduced in weight and size. Since the gas generating agent filled in the same combustion chamber is a gas generating agent even if the combustion temperature is different, the gas from the gas generating agent that is directly ignited and combusted by the electric igniter is also an airbag. It can be used as an inflating gas, whereby the filling amount of the gas generating agent for inflating the airbag can be reduced.

  In the gas generator of the present invention, when a gas generating agent having a high combustion temperature that generates ammonia by combustion is used, a gas generating agent that generates NOx by combustion is used for the gas generating agent having a low combustion temperature. Even if it is used, each can be converted into nitrogen gas by the reaction of the generated NOx and ammonia, so the amount of NOx discharged can be reduced more reliably and the amount of ammonia discharged can also be reduced.

According to the gas generator of the present invention, the combustion temperature of the gas generating agent in the entire gas generator can be lowered, thereby achieving a smaller gas generator with a simpler coolant filter. Can do. Furthermore, since the combustion temperature of the gas generating agent can be kept low, gas components such as NOx can be reduced during combustion of the gas generating agent. In the gas generator of the present invention, the ignitability and flammability of the gas generant are reduced while reducing the combustion temperature of the gas generant, that is, generally using a gas generant with poor ignitability. It is sufficient to ensure the reliability of the operation of the gas generator. That is, according to the present invention, it is possible to solve the conflicting technical problems related to the ignitability and combustibility of the gas generating agent.
In the gas generator of the present invention, it is easy to adjust the output of the gas generator by adjusting the total filling amount of the gas generating agent that fills the same combustion chamber and causes different combustion temperatures and the mutual filling ratio. Can be done.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a sectional view in the axial direction of a gas generator for an air bag of the present invention. In the following, when referring to the vertical relationship with the top or bottom, FIG. 1 is used as a reference. Further, the axial direction means the axial direction of the housing, and the radial direction means the radial direction of the housing.

  In the gas generator 10, an outer shell container is formed by a housing 11 formed by joining a diffuser shell 12 and a closure shell 13 that forms an internal accommodation space together with the diffuser shell 12. The diffuser shell 12 and the closure shell 13 are welded at the welded portion 14. In FIG. 1, other black portions also indicate welds.

  The diffuser shell 12 is provided with a required number of gas discharge holes 17 and 18 arranged in the circumferential direction. The gas discharge holes 17 and 18 are closed with an aluminum seal tape 75. The gas discharge holes 17 and the gas discharge holes 18 arranged in the circumferential direction may have the same diameter or different diameters.

  A substantially cylindrical inner cylinder 15 is disposed in the housing 11, the upper peripheral edge of the inner cylinder 15 is joined to the ceiling surface 12 a of the diffuser 12, and the lower peripheral edge is joined to the bottom surface 13 a of the closure shell 13. As a result, a space partitioned from the external environment is formed inside the housing and outside the inner cylinder 15, and a space (a first combustion chamber of the first combustion chamber) that accommodates a first gas generating agent 20 b described later in the space. Part) is secured. A single collar 33 that fixes the first igniter 31 and the second igniter 32 is provided in the lower opening of the opened inner cylinder 15 to seal the inside of the inner cylinder 15. The first igniter 31 and the second igniter 32 are devices that control the operation of the gas generator via a connector, a lead wire, and the like when the airbag module including the gas generator 10 is attached to a vehicle ( Or a power source).

  In the inner cylinder 15, a partition wall 40 that partitions the space in the inner cylinder 15 vertically is provided. The partition wall 40 is formed as a flat plate-shaped partition wall having a skirt portion 41 surrounding the second igniter 32 and a second through hole 52 formed within a range surrounded by the skirt portion. The inner cylinder 15 is fitted into the stepped portion 16 from below. Since the partition wall 40 is fitted into the stepped portion 16 of the inner cylinder 15 as described above, even when the first igniter 31 is activated, it is prevented from moving upward due to the pressure during operation. Further, since the inner diameter of the skirt portion 41 is set to be substantially the same as the outer diameter of the ignition portion of the igniter 32, and the skirt portion 41 is in close contact with and surrounds the ignition portion, the second igniter The flame generated by the operation of 32 moves straight only in the direction of the second through hole 52.

  In the lower space (that is, the space closed by the collar 33) in the inner cylinder 15 that is partitioned by the partition wall 40, the second ignition is performed by the skirt portion 41 (that is, the skirt portion 41). The first igniter 31 and the first gas generating agent 20a filled in the aluminum cup 35 are disposed in a space partitioned from the space where the vessel 32 exists. Therefore, in the gas generator shown in the present embodiment, the first gas generating agent 20a disposed in the same space as the first igniter 31 and the radially outer side of the inner cylinder 15 are partitioned as the first gas generating agent. The first gas generating agent 20b disposed in the space is used.

  The combustion temperatures of the first gas generating agents are different from each other, and the first gas generating agent 20a disposed in the same space as the first igniter 31 has a high combustion temperature. As the first gas generating agent 20b disposed in the space divided into two, one having a low combustion temperature is used. The first gas generating agent 20a having a high combustion temperature has a shape without holes, and the size (diameter and length) per grain is smaller than that of the first gas generating agent 20b having a low combustion temperature and the combustion temperature is high. The first gas generating agent 20b is a single-hole cylindrical gas generating agent. However, the shape of the gas generating agent (first and second gas generating agents) that can be used in the gas generator of the present invention is not particularly limited, and is a disc shape having a through hole or a non-through hole (concave portion). Cylinders having through-holes or non-through-holes (concave portions) can be used, and a gas generating agent having a high combustion temperature and a gas generating agent having a low combustion temperature have the same shape. You can also

  A space radially outside the inner cylinder 15 in which the first gas generating agent 20b having a low combustion temperature is accommodated and a space in which the first igniter 31 in which the first gas generating agent 20a having a high combustion temperature is accommodated are present. Means that the gas generating agent in both spaces communicates with each other through the first through hole 51 and is ignited and combusted in association with the operation of the first igniter 31. Thus, the first gas generating agents 20a and 20b having different combustion temperatures are filled in the same combustion chamber (first combustion chamber 20). .

  By disposing the partition wall 40 having the skirt portion 41 in the inner cylinder 15, the second combustion chamber 25 and the two igniters are separated, and the first igniter 31 and the second igniter 32 are separated. Has been. Thus, the ignition energy (flame, combustion gas, etc.) generated by the operation of the first igniter 31 flows exclusively into the first combustion chamber, passes through the second ignition means chamber, and further passes through the second through hole 52 to the second. Intrusion into the combustion chamber 25 is prevented.

  The gas generating agent 20 a filled in the aluminum cup 35 exists immediately above the first igniter 31, and the first through hole 51 provided in the lower portion of the side wall of the inner cylinder 15 It is provided at a position substantially facing the center, and this position is not facing the traveling direction of the flame generated by the operation of the first igniter 31. Note that an aluminum or stainless steel seal tape 60 is attached to the first through hole 51 from the inside.

  As described above, the first through hole 51 and the aluminum cup 35 in which the gas generating agent 20a is accommodated are arranged so as to face each other. It is burned evenly.

  Furthermore, the first through hole 51 is provided in the lower part of the inner cylinder 15 and is outside the space where the first gas generating agent 20b exists and is provided so as to face the peripheral wall surface of the housing. Inside the filter 65, a shielding plate 66 is provided at a position facing the first through hole 51. The shielding plate 66 in the present embodiment includes a cylindrical portion 92 and an outwardly flanged circular portion 93 integrally formed on one side (the lower side in FIG. 1). The circular portion 93 is a bottom surface. The cylindrical portion 92 covers a predetermined range (a height range of about 1/2 to 2/3 with respect to the total height of the cylindrical filter 65) while being in contact with 13a. Is formed.

  As a result of providing such a shielding plate 66, the high temperature gas and flame (energy generated by the combustion of the gas generating agent 20a) generated by the combustion of the first gas generating agent 20a released from the first through-hole 51 are shielded. Colliding with the plate 66 (especially the cylindrical portion 92), the energy traveling direction is changed from the radial direction to the axially upward direction and directed toward the space where the first gas generating agent 20b exists. Thereby, the overall ignitability of the first gas generating agent 20b is improved. Accordingly, it is preferable that the axial length of the shielding plate 66 extends at least above the first through hole 51. However, the shielding plate 66 may be formed by covering the entire inner peripheral surface of the filter 65 and partially providing a plurality of gas vent holes. In this case, the same action as shown in FIG. An effect can be obtained. Further, on the outer side of the filter 65, as in the case of the shielding plate, a shielding plate having a cylindrical portion 92 and a circular portion that is integrally formed on one side (the lower side in FIG. 1) and covers the outer periphery of the filter 65. (Not shown) can also be provided.

  Further, the shielding plate 66 can be positioned with respect to the housing by bringing the outer peripheral edge of the circular portion 93 into contact with the bent portion 94 of the housing. In addition, the filter can be positioned during assembly by bringing the inner peripheral surface of the filter 65 into contact with the lower outer peripheral surface of the cylindrical portion 92. The cylindrical portion 92 is formed and arranged so as to ensure an annular gap 71 between the inner peripheral surface of the filter 65. As a result, the combustion gas (that is, the gas for inflating the airbag generated by the combustion of the gas generating agent) also enters the gap 71, so that the filter efficiency and the cooling efficiency are improved.

As described above, in the configuration or structure on the first combustion chamber 20 side provided in the housing 11, the first gas generating agent 20 a having a high combustion temperature filled in the aluminum cup 35 by the operation of the first igniter 31. The whole is burned quickly and evenly. Then, the flame breaks the seal tape 60 and fills the gas generating agent 20b having a low combustion temperature in the same first combustion chamber existing outside the inner cylinder 15 from the first through hole 51 at the lower side wall of the inner cylinder 15. The first gas generating agent 20b having a low combustion temperature is ignited and burned. At that time, the first gas generating agent 20b having a low combustion temperature is generally inferior in ignitability, but the first gas generating agent 20a having good ignitability burns sufficiently and for a long time. Even the first gas generating agent 20b having such a low combustion temperature can be ignited and burned quickly and reliably. Further, the combustion heat of the entire first gas generating agent generated in the first combustion chamber is reduced by the amount of the first gas generating agent 20b having a low combustion temperature being used.

  Further, the space above the partition wall 40 in the inner cylinder 15 is formed as a second combustion chamber 25, and in the second combustion chamber 25, the second gas generating agent 25 a and the second gas generating agent 25 a having different combustion temperatures are connected to each other. Both gas generating agents 25b are accommodated. In the present embodiment, the second gas generating agent 25a having a high combustion temperature is filled on the side (lower side) where the partition wall 40 is provided in the second combustion chamber 25, and the second low combustion temperature is provided above the second gas generating agent 25a. The gas generating agent 25b is filled. The two types of second gas generating agents 25a and 25b having different combustion temperatures are divided into a partition member, that is, a partition plate 96 having a communication hole 95 for each type in the same second combustion chamber 25. It is divided and filled with. The communication hole 95 can be closed with a seal tape (not shown). The partition plate 96 is press-fitted from under the inner cylinder 15, and it is desirable that the seal tape 60 is pasted after the partition plate 96 is press-fitted so that the seal tape 60 is not damaged during press-fitting.

  The space in which the second gas generating agent 25a having a high combustion temperature is accommodated and the space in which the second gas generating agent 25b having a low combustion temperature are accommodated communicate with each other through the communication hole 95, and the gas in both the spaces. Since the generating agent is ignited and combusted in connection with the operation of the second igniter 32, both spaces are combined into one combustion chamber (second combustion chamber 25), and the combustion is performed. The second gas generating agents 25a and 25b having different temperatures are filled in the same combustion chamber (second combustion chamber 25).

  Particularly in the present embodiment, also for the second gas generating agent, as with the first gas generating agent, the second gas generating agent 25a having a high combustion temperature has a shape without holes, and the size (diameter) per grain. , Length) is smaller than the second gas generating agent 25b having a low combustion temperature. The second gas generating agent 25b having a high combustion temperature is a single-hole cylindrical gas generating agent. These second gas generating agents are arranged so as to be ignited (or transferred) in the order of the igniter 32, the second gas generating agent 25a, and the second gas generating agent 25b.

  Since the partition plate 96 is press-fitted into the second combustion chamber 25 and arranged in a state where the arrangement location can be arbitrarily adjusted, the second gas generating agents 25a and 25b are filled at an arbitrary mixing ratio. Can be done. In the case of the present embodiment, the filling amount of the gas generating agent 25b having a low combustion temperature is set larger than that of the gas generating agent 25a having a high combustion temperature, thereby suppressing the combustion temperature generated in the second combustion chamber 25 as a whole. ing.

  In addition, since the arrangement location of the partition plate 96 can be arbitrarily adjusted, by arbitrarily adjusting the filling ratio of the second gas generating agents 25a and 25b having different combustion temperatures, the gas generated from the second combustion chamber can be adjusted. The output of the gas generator can be adjusted by adjusting the temperature arbitrarily. Further, if the filling amount of the gas generating agent having a low combustion temperature is increased, the temperature of the gas generated from the second combustion chamber as a whole is lowered, and the amount of the filter 65 can be reduced. As a result, the entire gas generator can be reduced in size and weight.

  Further, since the combustion temperature of the second gas generating agent 25b is lower than that of the second gas generating agent 25a, generally, its ignitability is inferior, but in the gas generator shown in FIG. First, the second gas generating agent 25a having a high combustion temperature is ignited and combusted by the second igniter 32, whereby sufficient ignition energy is supplied to the second gas generating agent 25b having a low combustion temperature. The improvement of the combustibility of the 2nd gas generating agent accommodated in 2 combustion chamber 25 is achieved.

In this respect, boron nitrate (B / KNO ₃ ), which has been used as a conventional transfer powder, is used in powder form and burns out instantly, which is sufficient for the gas generating agent 25b having a low combustion temperature. It was difficult to supply ignition energy. Therefore, in the gas generator according to the present invention, sufficiently high ignition energy can be supplied to the second gas generating agent 25b for a relatively long time by the combustion of the second gas generating agent 25a having a high combustion temperature. This is very useful in that the gas generating agent 25b can be reliably ignited and burned. The use of the second gas generating agent 25a is also advantageous in that gas for inflating the airbag can be supplied.

  In the present embodiment, the gas generating agents 25a and 25b are separated by the partition plate 96. However, the gas generating agents 25a and 25b are mixed evenly without using the partition plate 96, and the second The gas generating agents 25a and 25b can be localized as shown in FIG. 1 without being arranged in the combustion chamber or using the partition plate 96. However, in terms of adjusting the combustion performance of the gas generating agents 25a and 25b, it is preferable to use a partition plate 96 in which communication holes 95 are formed. This is because the combustion performance of the gas generating agent 25a can be adjusted by adjusting the total opening area of the communication hole 95 with respect to the total surface area of the gas generating agent 25a. On the other hand, the combustion performance of the gas generating agent 25b is adjusted by adjusting the total opening area of the communication holes 80 (communication holes communicating the first combustion chamber 20 and the second combustion chamber) with respect to the total surface area. It becomes possible to do. However, if the gas generating agent is not required to adjust the combustion performance due to its characteristics, naturally, it is not necessary to adjust the combustion performance of the gas generating agent at the communication hole of the partition plate. In some cases, the communication holes can be formed sufficiently large, the partition plate itself can be eliminated, and two kinds of gas generating agents can be unevenly distributed or mixed.

  A bottomed cylindrical retainer 55 is fitted into the second combustion chamber 25 with the opening side down, and is fixed by pressing the inner wall 25a of the second combustion chamber 25 at the side wall tip 55a. Yes. The retainer 55 has a plurality of openings (nozzles) on the side wall, or the retainer 55 is entirely formed of a porous material such as a wire mesh, and has no substantial pressure loss. A gap 57 is provided between the inner walls 25a of the second combustion chamber 25 so as to ensure a gas flow path.

  As a result, the gas generating agent 25b does not come into contact with the communication hole 80, and therefore the communication hole 80 is not blocked by the unburned gas generating agent 25b in the vicinity of the communication hole 80. If the communication hole 80 is blocked with the second gas generating agent, the internal pressure in the second combustion chamber 25 excessively increases at the beginning of combustion, and the second gas generating agent blocking the communication hole 80 is combusted. Since the internal pressure is suddenly reduced by opening the holes 80, stable combustibility may be impaired. However, in the gas generator shown in the present embodiment, the communication holes 80 are blocked by the unburned gas generating agent 25b. Such a problem can be eliminated because it is never done. Similarly, a member that forms a gap between the gas generating agent 25a and the communication hole 95 (partition plate 96) may be used.

  The communication hole 80 is closed from the outside by a stainless seal tape 58. The seal tape does not open when the first gas generating agents 20b and 20a are combusted, and the material, the thickness, and the clogging are opened only when the second gas generating agents 25a and 25b are combusted. Thru | or a structure etc. are selected.

  In addition, also regarding the 1st combustion chamber 20 mentioned above, the filling ratio of gas generating agent 20b, 20a from which a combustion speed mutually differs can also be adjusted. An example of such an embodiment is shown in FIG. 1. For example, a retainer 98 that holds a gas generating agent 20 b having a low combustion temperature is arranged near the center in the housing axial direction, and a gas having a low combustion temperature is disposed on the diffuser 12 side. The gas generating agent 20b having a high combustion temperature is disposed on the closure 13 side. At this time, the gas generating agent 20a having a high combustion temperature is also disposed in the space portion 90 in which the second igniter is accommodated in the first combustion chamber. By making the retainer 98 press-fit, the filling ratio of both the first gas generating agents can be adjusted arbitrarily. However, as mentioned in the description of the second combustion chamber, it is preferable to increase the filling amount of the gas generating agent having a low combustion temperature also in the first combustion chamber in terms of light weight of the coolant and downsizing of the gas generator. .

  As in the gas generator described with reference to FIG. 1 above, in the dual type gas generator in which two combustion chambers are provided in the housing, two types of gas generating agents filled in the same combustion chamber are used. The adjustment of the filling ratio may be performed for only one of the first combustion chamber and the second combustion chamber, or for both combustion chambers.

  In the gas generator shown in the present embodiment, as the gas generating agents 20a and 25a having a high combustion temperature disposed in the first combustion chamber and the second combustion chamber, for example, a gas generating agent having a combustion temperature of 1700 to 3000 ° C. Can be used. As an example of this gas generating agent, it is a gas generating agent using nitroguanidine as a fuel and strontium nitrate as an oxidizing agent, and if necessary, a binder (sodium salt of carboxymethyl cellulose) and a residue collector (acid clay). Can be used.

As the first and second gas generating agents having a high combustion temperature, for example, the following composition can be used.
(A) about 25-55 wt%, preferably 30-40 wt% nitroguanidine (b) about 40-65 wt%, preferably 45-65 wt% strontium nitrate (c) about 1-20 wt%, Preferably 3-7% by weight of acid clay (d) about 3-12% by weight, preferably 4-12% by weight of binder, and the first and second gas generating agents having such a high combustion temperature are, for example, an outer diameter of 0 .8 to 4.0 mm, formed into pellets with a length of 0.8 to 4.0 mm, or an outer diameter of 1.2 to 6.0 mm, a length of 0.8 to 6.0 mm, and an inner diameter of 0 It can be formed in a single-hole cylindrical shape having a through hole of 5 to 2.0 mm.
Furthermore, as the first and second gas generating agents having a high combustion temperature, a gas generating agent as disclosed in Japanese Patent No. 3247929 can be used. The gas generating agent shown in Table 1 is included.

  On the other hand, a gas generating agent having a combustion temperature of 1000 to 1700 ° C., for example, can be used as the gas generating agents 20b and 25b having a low combustion temperature disposed in the first combustion chamber and the second combustion chamber. Examples of the gas generating agent include a gas generating agent using guanidine nitrate as a fuel and basic copper oxide as an oxidizing agent, and further, if necessary, the binder, residue collecting agent, or coolant (water What contains (aluminum oxide) can be used.

As the first and second gas generating agents having a low combustion temperature, for example, compositions containing the following components (a) to (c) can be used.
(A) The organic compound as the fuel is preferably 5 to 60% by mass, more preferably 10 to 60% by mass, and still more preferably 10 to 55% by mass;
(B) The oxygen-containing oxidant is 10 to 85% by mass of the component. In a preferred embodiment, the component (b) is (b-1) an oxidant (at least one selected from basic metal nitrates, nitrates and ammonium nitrates). From 10 to 85% by weight, more preferably from 20 to 70% by weight, still more preferably from 30 to 60% by weight, and (b-2) an oxidizing agent (from perchlorate and chlorate). The selected at least one oxidizing agent is preferably 0.5 to 20% by mass, more preferably 1 to 10% by mass, and still more preferably 1 to 5% by mass.
(C) 0.1-20 mass% of aluminum hydroxide, More preferably, it is 3-15 mass%, More preferably, it is 4-10 mass%.
Examples of the gas generating agent include the following compositions.
(Formulation example 1)
(A) Guanidine nitrate 30-60% by mass
(B) Basic copper nitrate 30-60 mass%
(C) Aluminum hydroxide 3 to 10% by mass
(Formulation example 2)
(A) Guanidine nitrate or melamine (b-1) Basic copper nitrate (b-2) At least one perchlorate selected from sodium perchlorate, potassium perchlorate and ammonium perchlorate (c) Water Aluminum oxide.
(Formulation example 3)
(A) Guanidine nitrate or melamine (b-1) Basic copper nitrate (b-2) Sodium chlorate or potassium chlorate (c) Aluminum hydroxide.
Furthermore, the composition formed by mix | blending any one or both of (d) component and (e) component with respect to said (a)-(c) component can also be used.
(D) The binder is preferably 20% by mass or less, more preferably 0.5 to 10% by mass, still more preferably 1 to 7% by mass;
(E) The additive selected from a metal oxide and a metal carbonate is preferably 20% by mass or less, more preferably 1 to 15% by mass, and still more preferably 3 to 10% by mass.
Examples of the gas generating agent include the following compositions.
(Formulation example 4)
(A) Nitroguanidine (b) Basic copper nitrate (c) Aluminum hydroxide (d) Guam gum.
(Formulation example 5)
(A) Melamine (b) Basic copper nitrate (c) Aluminum hydroxide (d) Carboxymethylcellulose sodium salt or guar gum.
(Formulation example 6)
(A) Guanidine nitrate (b) Basic copper nitrate (c) Aluminum hydroxide (d) Carboxymethylcellulose sodium salt or guar gum.
The first and second gas generating agents having a low combustion temperature have outer diameters of 1.2 to 6.0 mm, lengths of 0.8 to 6.0 mm, and through holes having an inner diameter of 0.5 to 2.0 mm. What was formed in the single-hole cylindrical shape which has can be used.
Furthermore, as the first and second gas generating agents having a low combustion temperature, the gas generating agents shown in Table 2 below can also be used.

In Table 2, GN is guanidine nitrate, NQ is nitroguanidine, BCN is basic copper nitrate [Cu ₂ (NO ₃ ) (OH) ₃ ], CMCNa is carboxymethylcellulose sodium salt, and BHTH ₃ is bitetrazole ammonium salt. The average particle diameter of basic copper nitrate in Table 1 is 4.7 μm, and the average particle diameter of aluminum hydroxide is 11 μm.
And what is preferable as a 1st and 2nd gas generating agent with a low combustion temperature contains the (a)-(c) component shown below, Furthermore, 0.1-20 mass% of aluminum hydroxide as a coolant, Preferably it contains 3-15 mass%, Most preferably, it contains 4-10 mass%.
(A) 5-60% by mass of guanidine nitrate as a fuel, preferably 10-60% by mass, particularly preferably 10-55% by mass,
(B) 10 to 85% by weight, preferably 20 to 70% by weight, particularly preferably 60 to 60% by weight, of basic copper nitrate as an oxidizing agent,
(C) 20% by mass or less of carboxymethylcellulose sodium salt as a binder, preferably 1 to 15% by mass, particularly preferably 3 to 10% by mass,

Each said gas generating agent can be used with the following usage-amounts (and the usage rate according to this usage-amount), for example.
First gas generating agent having a high combustion temperature: 0.5 to 15 g, preferably 1 to 15 g, particularly preferably 1.5 to 15 g
First gas generating agent having a low combustion temperature: 3 to 150 g, preferably 7 to 150 g, particularly preferably 12 to 150 g
Second gas generating agent having a high combustion temperature: 0.5 to 15 g, preferably 1 to 15 g, particularly preferably 1.5 to 15 g
Second gas generating agent having a low combustion temperature: 1 to 50 g, preferably 2 to 50 g, particularly preferably 3 to 50 g

  In the gas generator shown in the present embodiment configured as described above, gas generating agents 20b and 25b having low combustion temperatures are used in the first combustion chamber and the second combustion chamber, respectively. The temperature of the gas generated in each combustion chamber, and further the temperature of the gas generated in the entire gas generator are significantly reduced as compared with the case where a gas generating agent having a high combustion temperature is used. As a result, the generation of NOx during the combustion of each gas generating agent is reduced, and the filter 65 for purifying and / or cooling the combustion gas before being discharged from the gas generator is simplified. Can do.

    That is, in the gas generator shown in FIG. 1, combustion residues are removed from the combustion gas between the first combustion chamber 20 and the peripheral walls of the housing 11 (the diffuser shell peripheral wall 12b and the closure shell peripheral wall 13b). The cylindrical filter 65 for cooling the combustion gas is arranged, but since the temperature of the gas generated in the whole gas generator is kept low, a simpler one such as one having a large porosity Is used. The filter 65 is arranged so as to form a gap 72 between the peripheral wall of the housing 11.

  As the cylindrical filter 65 formed as a simple one, a thin metal wire (iron wire or the like) having a wire diameter of about 0.3 to 1.2 mm is wound in a cylindrical shape, and the thin metal wire is plain-woven and wound in multiple layers. After compression molding, plain weaving with wire diameter of about 0.3 to 0.8 mm, tatami weaving, twill mat weaving wire mesh or single or combined, ceramic fiber or metal fiber between these wire mesh The thing etc. which inserted | pinched can be used.

The structure of the cylindrical filter is appropriately selected according to the type of gas generating agent used, the amount used, and the difference in usage ratio between gas generating agents having different combustion temperatures, that is, the level of combustion temperature and the amount of combustion residue generated. Will be. For example, when a gas generating agent having a low combustion temperature (about 1000 to 1700 ° C.) and a small amount of combustion residue is used, the bulk density is 1 to 5 g / cm ³ , preferably 2 to ³ g / cm ³ , and the thickness is 3 to 3. The thing of 10 mm, Preferably 3-6 mm can be used.

A shielding plate 66 is disposed inside the cylindrical filter 65, and the gap (first gap 71) is provided between the cylindrical filter 65 and the inner cylindrical shielding plate 66. Instead, the portion of the cylindrical filter 65 that is in contact with the shielding plate 66 (the portion having the same width as the gap) has a sparse structure with a large porosity, and is in a state substantially the same as when a gap is provided. good. The sparse structure is for a dense structure having a small porosity, and when the bulk density of the dense structure is within the above range, the bulk density of the sparse structure should be 0.1 to 1.0 g / cm ^3. Can do. The width of the gap 71 and the sparse structure portion secured between the cylindrical filter 65 and the shielding plate 66 is preferably 0.5 to 3 mm, and more preferably 1 to 2 mm.

  Combining the cylindrical filter 65 with a shielding plate 66 that covers the inside of the filter and a shielding plate (not shown) that covers the outside of the filter, the combustion gas filtration (combustion residue filtration) and the cooling action are further improved. .

  Note that the seal tape 75 that closes the gas discharge holes 17 and 18 may burst at the same time or may only partially burst depending on the operation status of the igniter (only one operation, both operation simultaneously, operation with a time difference). It can also be set to.

  Next, the operation when two igniters are operated with a time difference in the air bag gas generator 10 will be described with reference to FIG.

  By the operation of the first igniter 31, the first gas generating agent 20 a having a high combustion temperature is ignited and burned, and the energy breaks the seal tape 60, passes through the first through-hole 51, and passes through the first combustion chamber 20. It is discharged into the outer space of the inner cylinder 15.

  At this time, the ignition energy released from the first through-hole 51 provided in the peripheral wall of the inner cylinder 15 collides with the shielding plate 66 facing the first through-hole 51, and its traveling direction is changed upward. The first gas generating agent 20b having a low combustion temperature existing in the traveling direction is ignited and burned. That is, the traveling direction of the ignition energy is changed from the radial direction to the axial direction by the shielding plate 66, and the ignition energy is supplied to the gas generating agent existing in both the radial direction and the axial direction. The ignitability of all the first gas generating agents present in the first combustion chamber 20 is improved.

  If the shielding plate 66 does not exist, the ignition energy released radially outward from the first through hole 51 is sufficiently given to the first gas generating agent 20b existing in the emission direction, but exists upward. It is difficult to transmit to the first gas generating agent 20b. Such a problem is particularly noticeable when a gas generating agent having low ignitability is used. Thus, as shown in the present embodiment, the use of the shielding plate 66 together with the filter 65 can solve the problem regarding the inefficiency of the ignition energy transmission. Furthermore, by using the shielding plate 66, it is also possible to prevent ignition energy from colliding with a part of the cylindrical filter 65 and damaging the cylindrical filter 65. Therefore, the position of the first through hole 51 in the axial direction is adjusted so as to exhibit the above-mentioned action / effect.

  In addition, since the communication hole 80 formed between the first combustion chamber and the second combustion chamber in the inner cylinder 15 is closed by the stainless steel seal tape 58, the combustion in the first combustion chamber 20 is performed. Gas does not flow into the second combustion chamber 25. All of the gas generated in the first combustion chamber 20 passes through the filter 65, ruptures the seal tape 75, and is discharged from the gas discharge holes 17 and 18 to an airbag (not shown).

  The gas generated by the combustion of the first gas generating agents 20b and 20a enters the cylindrical filter 65 from a portion (or gas vent hole) not covered with the shielding plate 66, and a part of the gas passes through the cylindrical filter 65 as it is. After moving in the axial direction, it reaches the gap 72 on the outer peripheral side of the filter 65. The remaining part of the combustion gas moves through the gap 71 secured on the inner peripheral side of the filter 65, then passes through the cylindrical filter 65 in the radial direction, and passes through the gap 72 on the outer peripheral side of the filter 65. To. Thereafter, the combustion gas ruptures part or all of the seal tape 75 and is discharged from part or all of the gas discharge holes 17 and 18 to inflate the airbag.

  Thus, since the gap 71 is secured on the inner peripheral side of the filter 65 by the shielding plate 66, the gas passing through the gap 71 passes through the cylindrical filter 65 in the axial direction. Thus, the entire cylindrical filter 65 is used, and a long contact time with the filter 65 is ensured, so that the cooling and filtering effect of the combustion gas is enhanced.

  Then, after the first igniter 31 is activated, the second igniter 32 is activated with a slight time difference. At this time, the flame generated by the operation of the second igniter 32 goes straight through the second through hole 52 and enters the second combustion chamber. Due to the penetration of ignition energy, first, the second gas generating agent 25a having a high combustion temperature in the second combustion chamber 25 is ignited and combusted, and the second gas generating agent 25b having a low combustion temperature is ignited and combusted by the flame. . During the combustion of the second gas generating agent, as described above, the opening area of the communication hole 80 above the inner cylinder 15 (or the opening when the retainer 55 has an opening) and the height position where the communication hole 80 is formed are determined. Since it is adjusted, the fire around the entire second combustion chamber 25 is good, and the ignition and combustibility of the second gas generating agent is good. Further, when the communication hole 80 is closed with the seal tape 58, the initial combustibility of the second gas generating agent is improved.

  The gas generated in the second combustion chamber 25 is released in the radial direction from the communication hole 80 formed in the inner cylinder 15 and flows into the first combustion chamber 20. After that, the air bag is cooled and purified and discharged from the gas discharge holes 17 and 18 to further inflate the airbag.

Example 1
A gas generator for an air bag shown in FIG. 1 was produced. Details are as follows.
(1) Use amount of gas generating agent First gas generating agent having a high combustion temperature: 7 g
First gas generating agent with low combustion temperature: 90 g
Second gas generant with high combustion temperature: 15 g
Second gas generating agent with low combustion temperature: 20 g
(2) Shape and composition of gas generating agent <first and second gas generating agents having a high combustion temperature>
It has the following composition in the form of a pellet having an outer diameter of 1.5 mm and a length of 1.5 mm (combustion temperature 2200 ° C .; generated gas amount 2.5 mol / 100 g).
Nitroguanidine 34.4% by mass
55.6% by mass of strontium nitrate
Carboxymethylcellulose sodium salt 10.0% by mass
<First and second gas generating agents with low combustion temperature>
It is a single-hole cylindrical shape having through-holes with an outer diameter of 4.5 mm, an inner diameter of 1.2 mm, and a length of 4 mm, and has the following composition (combustion temperature 1200 ° C.).
Guanidine nitrate 41% by mass
49% by mass of basic copper nitrate
Carboxymethylcellulose sodium salt 5 mass% or less Aluminum hydroxide 5 mass%

  In the above-described embodiments and examples, the description has been made based on the gas generator using two igniters, but the present invention is not limited to the number of such igniters, However, it can also be used for a single gas generator. For example, like the gas generator shown in FIG. 1 of Japanese Patent Laid-Open No. 10-95303, an inner cylinder is arranged in a housing, and a combustion chamber is formed in which a gas generating agent is filled outside the inner cylinder. In addition, in the gas generator in which an igniter is disposed on the lower side in the inner space of the inner cylinder and a transfer agent is disposed on the upper side, the gas generator having a high combustion temperature is filled instead of the transfer agent in the inner cylinder. It is also possible to fill the outer combustion chamber with a gas generating agent having a low combustion temperature.

Sectional drawing along the axial direction of the gas generator for airbags.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Gas generator 11 for airbags 12 Housing 12 Diffuser shell 13 Closure shell 14 Welding part 17, 18 Gas discharge hole 20 1st combustion chamber 20a 1st gas generating agent 20b with a high combustion temperature 20b 1st gas generating agent 25 with a low combustion temperature 2nd combustion chamber 25a 2nd gas generating agent with high combustion temperature 25b 2nd gas generating agent with low combustion temperature 31 and 32 Igniter 33 Igniter collar 35 Aluminum cup 40 Partition 55 Retainer 65 Filter 66 Shielding plate 96 Partition plate 98 Retainer

Claims (7)

A gas generator comprising a housing having a gas discharge hole, an ignition means as an operation start means of the gas generator, and a gas generating agent that generates a gas for inflating an airbag by ignition combustion,
The gas generating agent is filled in one or more combustion chambers defined in the housing, and at least one of the combustion chambers is filled with at least two kinds of gas generating agents that generate different combustion temperatures. And
The two types of gas generating agents are gas generators in which a gas generating agent having a high combustion temperature has a shape without holes and a gas generating agent having a low combustion temperature is cylindrical.   Among the at least two types of gas generating agents that cause different combustion temperatures, the combustion temperature of the gas generating agent having a high combustion temperature is 1700 to 3000 ° C., and the combustion temperature of the gas generating agent having a low combustion temperature is 1000 to 1700 ° C. The gas generator for an air bag according to claim 1.   Of at least two types of gas generating agents arranged in the same combustion chamber, the gas generating agent having a high combustion temperature is an amount capable of igniting and burning the gas generating agent having a low combustion temperature, and the filling amount thereof can be arbitrarily adjusted. The gas generator for an air bag according to claim 1 or 2, which is filled as described above.   The at least two kinds of gas generating agents arranged in the same combustion chamber are partitioned and filled with a partition member having a communication hole for each type in the same combustion chamber. The gas generator for airbags as described. The gas generator for an airbag according to claim 4 , wherein the partition member is installed as a partition for the combustion chamber in accordance with an amount of each gas generating agent filled in the combustion chamber in which the partition member is disposed.   The one or two or more combustion chambers defined in the housing are defined in accordance with ignition means for igniting and burning the gas generating agent filled therein, and any one of the combustion chambers 1 is filled. Or the gas generator for airbags as described in any one of Claims 1-5 in which two or more types of gas generating agents are ignited and combusted by any one ignition means.   The ignition means comprises only an electric igniter that is ignited by an operating current, and the gas generating agent having the higher combustion temperature of the at least two kinds of gas generating agents is directly ignited by the operation of the electric igniter. The gas generator for airbags as described in any one of Claims 1-6 arrange | positioned in the position by which it is carried out.

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